Create DAO file.

app/src/main/java/com/hyperling/expensetracker/ExpenseDao.kt

@@ -0,0 +1,30 @@
+package com.hyperling.expensetracker
+
+import androidx.room.Dao
+import androidx.room.Delete
+import androidx.room.Query
+import androidx.room.Upsert
+import kotlinx.coroutines.flow.Flow
+
+@Dao
+interface ExpenseDao {
+
+    // 2024-12-28
+    //   If these complain about return type errors, try upgrading
+    //   the ROOM version, otherwise remove the SUSPEND keyword.
+    @Upsert
+    suspend fun upsertExpense(expense: Expense)
+
+    @Delete
+    suspend fun deleteExpense(expense: Expense)
+
+    @Query("SELECT * FROM expense ORDER BY name ASC")
+    fun selectExpensesName(): Flow<List<Expense>>
+
+    @Query("SELECT * FROM expense ORDER BY rate ASC")
+    fun selectExpensesRate(): Flow<List<Expense>>
+
+    @Query("SELECT * FROM expense ORDER BY cost ASC")
+    fun selectExpensesCost(): Flow<List<Expense>>
+
+}